Instant message service has been applied to mobile communication networks and the Internet. The mobile communication networks may include the existing 2nd Generation Network (2G), 2.5 Generation Network (2.5G), the developing 3rd Generation Network (3G), and the IP Multimedia Subsystem (IMS), etc.
Instant message service is known as a kind of mobile data service for person-to-person or person-to-group messages based on Presence service.
The Open Mobile Alliance (OMA) institutes standards for the mobile instant message. Two types of instant message systems exist in the current specifications: one is the instant message system based on the Wireless Village (WV), which is based on protocols carried by Hyper Text Transport Protocol (HTTP)/Wireless Access Protocol (WAP)/Short Message Service (SMS) Protocol. The system is capable of supporting 2.5G/3G network, and is mainly applied to the traditional communication networks; the other is the instant message system based on the SIP/SIMPLE, which is based on protocols carried by SIP/SIMPLE and is mainly applied to the next generation IP network based on the IMS. For an end-user, the above WV and SIMPLE protocols are transparent, that is, whether you are a WV user or a SIMPLE user, you cannot be aware of any differences while using the services in the two instant message systems.
Search function, also called search service, is an important characteristic of the instant message system. Both the WV-Instant Message & Presence Service (WV-IMPS) instant message system and the SIMPLE IM system need to support the search function, and thereby from the aspect of the user, it is desired to use the search function of either system seamlessly.
In the related art, the user of a WV-IMPS instant message system (referred to as an IMPS user for short) can search for either a chat room, a member in the chat room, or a chat history, etc. in the WV-IMPS instant message system, whereas the user of a SIMPLE IM system can search for a chat room, a member in the chat room, or a chat history, etc. in the SIMPLE IM system.